1. Field
Quantum dots, production methods thereof, and electronic devices including the same are disclosed.
2. Description of the Related Art
The physical characteristics (e.g., energy bandgaps and melting points) of nanoparticles that are known as intrinsic characteristics depend on their particle size, unlike bulk materials. For example, a semiconductor nanocrystal, also known as a quantum dot (QD), is a semiconductor material having a crystalline structure with a size of several nanometers. Quantum dots have such a small size that they have a large surface area per unit volume and exhibit quantum confinement effects, and thus have different physicochemical characteristics from the characteristics of the bulk material. Quantum dots may absorb light from an excitation source, and may emit energy corresponding to an energy bandgap of the quantum dot. In the quantum dots, the energy bandgap may be selected by controlling the sizes and/or the compositions of the nanocrystals. Also, QDs have desirable photoluminescence properties and have a high color purity. Therefore, QD technology is used for various applications, including a display element, an energy device, a bio-light emitting element, or the like.
The quantum dots may be synthesized in a vapor deposition method such as metal organic chemical vapor deposition (MOCVD) and/or molecular beam epitaxy (MBE), or in a wet chemical method by adding a precursor to an organic solvent to grow crystals. In the wet chemical method, colloidal quantum dots may be prepared, and the quantum dots are coordinated with an organic material such as a dispersing agent on its surface during the crystal growth, and thereby the organic material controls the crystal growth. Therefore, the quantum dots may have a uniform size and shape, and semiconductor nanocrystal particles having various compositions and/or structures (e.g. core/shell) may be more easily synthesized in the wet chemical method than in the vapor deposition method.
The prepared quantum dots are separated and/or rinsed, and may be processed in a form of a composite including the quantum dots dispersed in a matrix such as a polymer for a final application. In the above processes, photoluminescence characteristics of the semiconductor nanocrystals may be degraded. Therefore, there is a need to develop semiconductor nanocrystals having improved stability and photoluminescence characteristic.